Process of extracting ellagic acid.



Mirna STATES1 PATENT OFFICE:

ADOLF I-IEINEMANN, OF EBERSWALDE, GERMANY.

PROCESS OF E XTRACTING ELLAGIC ACID.

SPECIFICATION forming part Of Letters Patent N0. 706,411, dated August5, 1902.

Application filed October 26. 1901. Serial No. 80,128. (Specimens) Toall whom, it may concern:

Be it known that I, ADOLF HEINEMANN, Ph. D., of Eberswalde, in theKingdom of Prussia and Empire of Germany,have invented certain new anduseful Improvements in Processes of Extracting Ellagic Acid from TanningMaterials Containing the, Same, of which the following is aspecification.

It has been known for some time that ellagic acid (O H O -l-2H O) isfound in divi-divi, algarrobilla, and similar tanning materials. Theprocesses heretofore used for obtaining it from these crude materialswere very deficient and did not meet the requirements of a technicalprocess adapted for practical use. Barth and Goldschmidt (Bertchte derChemischen Gee, Vol. XI, page 846) have produced ellagic acid fromdivi-divi by treating the crushed husks with alcohol at ordinarytemperature. Any process which is based on the extraction of ellagicacid by means of alcohol is, however, of little practical value onaccount of the very slight solubility of the acid in alcohol. Oobenzl(lli'onatsheftefit'r Chemt'e, 1, 671) recommends that the crushed andpulverized husks should be heated with water for several days and theextract evaporated while adding sulfuric acid until a syrup results. Tothis syrup is added boiling Water, from which the acid is precipitated.By this process, however, not all the acid contained in the husks can beobtained, as I have found that only a part of the acid is present in afree soluble form in the crude material. A considerable quantity of theacid is present in combination with other substances, probably as aglucoside, which is insoluble in water. The process proposed byOobenzlhas, however, the very important disadvantage that sulfuric acidhas to be added to the extract and that the extract filtered off fromthe ellagic acid is of no value. Lastly, it is impractical anduneconomical to evaporate the extract first to a syrup and then to addboiling water to this syrup.

I have discovered the important fact that the ellagic acid contained ina diluted tanning extract is present in the amorphous state and becomescrystalline when the extract is evaporated to a specific gravity of 1.2;It is, furthermore, insoluble in an aqueous solution of the specificgravity of 1.2. These two observations permit the separation of all theellagic acid that is present in an extract of the specific gravity of1.2 by means of filtration, suction, or centrifugal force. Theproduction of ellagic acid from a more concen- .trated extract is morediflicult, requires more time, and gives an impure product.

My invention consists, therefore, of a pro cess of producing ellagicacid from tanning materials containing it by concentrating the extractof the crude materials to a specific gravity of 1.2 and then separatingthe crystalline acid from this extract in any suitable manner.

To practically carry out my improved process, the crude material isextracted by means of boiling Water. The extract is then drawn off fromthe husks and evaporated to a specific gravity of 1.2. The ellagic acidis deposited in crystalline form and is separated from the mother-liquorby filtration, suction, or centrifugal force. The remaining extractedhusks are heated with dilute sulfuric or other acid, which latter isthen filtered 0E. The ellagic acid still contained in the extractedhusks is set free by this inversion and obtained from the residue bytreatment of the latter with sodium hydrate and ammonium chlorid,following the process described in German Patent No. 123,128.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- 1. The process herein described of producing ellagicacid from tanning materials containin g it, which consists inconcentrating an aqueous extract of the crude tanning substances to aspecific gravity of 1.2, and then separating the crystalline andinsoluble ellagic acid from said extract, substantially as set forth.

2. The process herein described of producing ellagic acid from tanningmaterials containing it, which consists in concentrating an aqueousextract of the crude tanning sub stances to a specific gravity of 1.2,separating therefrom the crystalline insoluble ellagic my invention Ihave signed my name in presacid,invertlzling the ellaglilo-acid compoundconence of two subscribing witnesses. tained in t eextracted usks byboiing them with a suitable acid, filtering off the acid, and ADOLFHEINEMANN' 5' separating the ellagic said set free by the in- Witnesses:7

version from the residue. L. OTTEMANN,

In testimony that I claim the foregoing as CONRAD PALM.

